The present invention relates generally to optical spectrometers, and more particularly to planar spectral filter optical spectrometers.
Optical spectrometers isolate individual wavelength components of light radiated from a source to measure wavelength-specific properties of the source. Scientists use optical spectrometers to analyze characteristics of various specimens, such as geological samples, biomedical samples, etc. Some optical spectrometers include a Fabry-Perot filter, a lens, and a detector array. The filter generates a spatial interference pattern based on the incident light from the source, while the lens images the spatial pattern onto the detector array. Detector elements in the detector array convert sensed light to an electrical output signal.
Fabry-Perot spectrometers are particularly useful for astronomical light sources and other light sources having modest modal and spectral complexity. However, the radially symmetric spatial patterns generated by the Fabry-Perot filter and the free spectral range of the Fabry-Perot filter create degenerate spatial patterns. This severely limits the spectrometer's ability to analyze light from a spectrally complex source. As a result, conventional Fabry-Perot spectrometers generally cannot be used to analyze diffuse or spectrally complex light sources. In view of this, and in view of the limitations of other known spectrometers, there remains a need for alternative spectrometer designs.